Play With Friends In Prologue Area With This GTA Online Glitch

A glitch has been discovered allowing you to access the GTA V prologue area of North Yankton in GTA Online.
Once there, you'll be able to race around the snowy area as if it were any other part of the game, and discover a number of areas not featured in the campaign.

To access the area in GTA Online, you need to replay the opening mission offline by selecting it from the missions menu, then play through it until you exit the building and the police arrive.

Once this happens, you need to hit pause and get a friend to invite you to their GTA Online multiplayer game. This will cause North Yankton to appear on your GTA Online map. It'll be floating over the south-east part of the map, but you can still access it via helicopter.